 In 1848, despite opposition from his father, he sold Athelhampton which had been purchased by Sir Robert Long, 1st Baronet, in 1665.He succeeded his father as Earl of Mornington on 1 July 1857.Mornington died unmarried in Paris on 25 July 1863 from cancer of the tongue, and is buried at Draycot Cerne in Wiltshire.